To develop a non-invasive tracer method, using stable isotope (D3-methyl and 13C-methyl) labeled 3-MeH, to determine the plasma kinetics of 3-MeH in severely burned patients and in healthy controls. The information obtained by this method will help to set a parameter for evaluating severity of the muscle catabolic state after burn injury. This knowledge will help guide us in developing therapeutic strategies aimed at reducing muscle protein loss.